


Sinning Trinity

by Arcial



Series: Broken Trinity [2]
Category: Undertale (Video Game)
Genre: Alternate Universe - Mob, Alternate Universe - Underfell, Alternate Universe - Underswap, Angst and Fluff and Smut, Body Worship, Consensual Sex, F/M, Other Additional Tags to Be Added, You bone the skeleton(s)
Language: English
Status: In-Progress
Published: 2018-02-09
Updated: 2018-02-09
Packaged: 2019-03-15 16:56:33
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,911
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13617657
Author URL: https://archiveofourown.org/users/Arcial/pseuds/Arcial
Summary: The smut-filled parts from my fic Broken Trinity.





	Sinning Trinity

**Author's Note:**

> Originally part of Chapter 21 of Broken Trinity.  
> This was possible due to one of my dearest friends Costumebleh (it's been a while <3)

  
You replied by slowly raising your shirt, noticing the lights in his eyes dim slightly the higher you raised your blouse. You flinched as he crept towards your chest. “it’s alright kid. trust me.”

Closing your eyes, you shivered as you felt a cold sensation trace each and every one of your scars. “you’re beautiful,” you heard him mumble. Soon enough, your back was no longer on the wall, but on the bed, and the coldness turning warm.

As his warm tongue traced the scars around your breasts, you felt a moan slowly exit from your mouth. As you opened your eyes, you noticed Sans emitting a vibrantly blue tongue loosely dripping with glowing saliva. “so beautiful kid,” he repeated before he kissed your neck. “would you trust me even more?”

You nodded, watching as Sans pull off his dress shirt and toss it somewhere nearby. Observing, you noticed that compared to the taller skeletons’ figures, Sans’ were much smaller, but it was as if his thicker-sized bones were to compensate for it.

Whilst kissing your neck, you felt the palm of his skeletal hand traveling down to your waist, and his other hand slowly circling your nipples. You moaned as his tongue exchanged spots with the hand, causing sparks of lust in your sensitive nerves.

With him exchanging between where to pay attention, you began arching every time you felt the heat radiating off his tongue coming closer to one of your breasts. You were so lost in the pleasure, you almost didn’t realize his eyes seeking consent as his hands were slowly tugging your pants down.

You replied by stroking the back of his spine, causing him to flinch from your touch and turn away from your eyes. You sat up, fearing that you might have hurt him. “Sans! I’m sorry are you alright?”

Your worry was eased as he turned back to you with embarrassed eyes. “y-yeah, you just caught me off guard is all.”

Oh?

Out of curiosity, you fluttered your fingers into the divots of Sans’ spine. “Does it hurt when I do this?”

“N- _ahh-_ o, it does-  _ngh_ -’t,” he breathed, slowly arching into your touch. With pleasure, you slowly pushed him onto his back while placing your legs on both sides of his. “w-well kid, i don’t usually let people top but—  _nghmh!!”_

You cut him off by bending over to lick his sternum and loosely gripped his spine with both hands.

“f- _fuuuck,”_ you heard him breathe, slowly giving in to your treatment. Feeling your confidence grow with every moan, every whimper and suppressed sound, you kept your fingers stroking his spine and began to move yourself down towards his pelvis, ever so slightly sticking out of his pants.

As you lightly nibbled on the edges of his pelvis, adding a slight caress of teeth to the surface, a cerulean glow beneath his waistline began illuminating the room and something was definitely pressing insistently against the fabric. Looking up at his heart-filled eyes, you noticed him trying to tug his pants off, and you hesitantly followed suit.

You felt his eyes stray, devouring the sight of your nearly-naked body as you positioned yourself, reaching down to touch what emerged from the slit of his shorts. Curious, but not pressing without his permission.

When his dick emerged from his boxers, you took a second to admire the view. With a naked monster looking at you like you were everything at this very moment, his actions having stopped as soon as he was revealed. Compared to a regular human’s his dick was a bit shorter in length, but was rather intimidating in width. Up close, you even noticed a few ridges along the side which made you quiver in anticipation.

“h-hey kid,” he stuttered, getting visibly uncomfortable the longer you stared, “it’s not  _that_ weird, is it?”

In reply, you instead leaned down to press your tongue against his leaking slit, where small drops were already starting to form, letting your actions speak louder than any words. You could feel him tense at this, and a garbled moan sounded from above, letting you know that he had most likely choke out his voice.

“k-kid,  _please_ -” When you then proceeded to slowly mouth around the head, you felt boney fingers gently tangling in your hair, “don’t- not if you’re not comfortabl-  _ah!”_ the rest was silence by your hand coming up to press against the curve of his pelvis. You were very comfortable, thank you very much.

Now you wanted  _him_ to feel the same.

Continuing your one hands’ exploration of the tiny nicks and crevices his lower body provided, you wrapped your other around where the base of his dick seemingly blended in with bone.

Slowly, you spread your lips across the impressive width and started to push down his shaft. You took care to press your tongue against the small ridges, and slightly bobbed your head as you moved. Making sure to hollow your cheeks, you felt that you were starting to reach the borders of your ability, just as you just about reached his base. With a hum, you removed your hand to instead use it for leverage. It took a few awkward movements up and down, with his fingers approvingly massaging your scalp before you managed to find a comfortable pace.

While blowing somebody off never had really been your favorite sex act, the guttural groan that escaped the skeleton above you definitely made it  _so_ worth it.

It didn’t take very long, with you being able to fit his whole length into your mouth and slightly down your throat, there was very little Sans could do to prevent the inevitable. His legs on each side of you started to shake, his fingers twitching and you knew that he was starting to get close.

With that in mind, you made sure the next time you moved upwards, to let the head of his cock to almost leave your mouth, your lips just barely there as your tongue greedily pressed against the slit, licking up all the precome and pressing even slightly into the crevice where the fluid erupted from.

A shower of pet names escaped from the heated skeleton between needy moans and whines, and you let yourself tease him for a few more moments before resuming your previous act. The pace you set was faster, a bit sloppier, as you wanted to hear what sound Sans could make when he finally came and also felt your own arousal press low in your belly.

For a few more moments, Sans seemed to try and tug your mouth off of him. A clear signal for what was about to happen and you took just the liberty to bob your head twice more, raking your nails gently across bone before pulling off. But that seemed to be enough, as a long deep-throated moan emitted from Sans, long hot streaks of cum sprouting free and streaking across your face. Aw, the poor guy was pent up.

You licked up what managed to land near your mouth, keeping eye contact with Sans all the while. That led to him groaning and grasping your face to pull you close, and before you knew it, his tongue was slowly lapping up what drops you had missed before finally delving back into making your knees weaken whilst kissing you.

“Oh  _fuck_ kid. didn’t have to do that for me.” A purr almost resounds from his chest following the words, clearly hinting that while he hadn’t expected it, he certainly approved, “now, let’s make sure to return the favor, hmm?”

And without much of a chance to digress, not that you really would, that heat  _definitely_ needed some attention, you suddenly found yourself in the opposite position. One smug skeleton settling between your legs, hands reaching around to cup your ass and easily press you closer.

“I want to show you just how beautiful you are, and you deserve it so, so much.” And without even giving you much room to reply, he delves right in.

You’d just experienced how that tongue could work when just kissing you, so it shouldn’t have come as a surprise that he knew what he was doing. But  _still_ , when it pressed expertly around your clit, circling the little nub with toe-curling precision, you couldn’t help the moan escaping your lips. Your thighs came to press encouragingly around his skull, rewarding you with a slight vibration added to the motions already administered to your sex.  _Fuck that felt good._

When one of his hands moved from your ass, instead pressing an attentive digit to your entrance, you couldn’t help the repetitive whispers of; “Sans, Sans, S-Sans,” as he was making a thorough mess out of you and you couldn’t do much more than let it happen.

With first one digit pressing and entering your heat, you felt a spike in pleasure, making you shiver as he first stretched you to comfortably fit one and then two fingers. The rough texture and the width of his fingers could have almost just been enough to set you off within minutes, but the insistent tongue prying away every ounce of your sanity made it all the shorter.

The vibrations didn’t falter, tongue moving more forcibly, edging you closer and closer to release. But you wanted it to last a little longer, let the small saps of pleasure stretch a little further until you couldn’t make sense of much more than the touch of the monster and the white static blurring out your mind as you felt your last restraints snap.

Your head snapped back as a moan left your lips, legs keeping Sans in place as the sweet waves of ecstasy drove through your body, making your spine arch off the bed. As if motivated by your euphoric moan, he watched your body writhe in pleasure as he helped you down from your high.

You watched as he parted with the smuggest look on his face. “ready?” he smiled, placing each of your legs on his shoulders. With a lazy smile, you nodded with a heart full of love for the skeleton in front of you.

Being unable to reply with words, all you could do was moan when you felt his erection rub your entrance— the moan ever so increasing the moment he pushed into you. He grasped your thighs to leverage himself and pressed his member into your opening. “ _damn_ ,” he breathed, trying to calm himself. “just tell me when to stop, ‘kay?”

He started slow, to get you to adjust to his unique size, getting ever so slowly faster as the ridges of his length hit your sweet spot again and again. When he noticed you biting the bed cloth to keep your voice down, he pulled your face to him and kissed you. “let me hear your voice,” he grunted, increasing the speed of his thrusts.

Unable to cover your mouth up as he held both of your arms above your head, you began gasping his name. “that’s it,” you heard him say before placing a digit on your clit. With one hand buried between your legs, mercilessly stimulating your nub, you begin chanting his name and he responded with a growl that sent vibrations throughout your bodies.

With one more thrust, you screamed out his name as you came from his ministrations, him following soon after, emptying on top of you.

 

 


End file.
